Tuesday, March 20, 2012

In part I of my interview with performance and spine expert, Dr. Stuart McGill, we covered a lot of ground. Dr. McGill is mostly known for his approach to "core training," but that term probably doesn't mean what you think it does. When you implement the training techniques that Dr. McGill covers in these interviews your entire body will become stronger and more explosive, not just your abs.
With that in mind, let's get back to the discussion and you'll understand why Dr. McGill is one of the most sought after performance experts across the globe.Chad Waterbury: Stu, the last time we met up for beers you asked me where I think the core is. I told you that I consider it everything from your head down to your toes. You seemed pleased with that answer. Or maybe it was just the lager talking? Care to elaborate?

Dr. Stuart McGill: To me the definition is context specific. Take the example of a MMA fighter and measure the biomechanics of hitting hard – at the instant the fist or shin contacts the opponent the whole body is stiffened with a pulse. This creates "effective mass" and results in the opponent being hit with the full mass of the striker. The entire body can be considered the stiffened core.

Contrast this with a standing one-arm press. It doesn't matter how much one can bench press because when standing you can only create a push force with a magnitude of half your body weight. Furthermore, the force development is limited by the ability of their torso and abdominal musculature to prevent twisting motion. Here I think the concept of the core would be more focused.

CW: In the first part of this interview you gave us a progression of core exercises that have no, or relatively low, rotational velocity. However, some sports such as golf mandate that movement pattern, even if it's high risk. Once a guy has worked through the progression, which exercise do you recommend to train higher rotational velocity?

SM: If we're talking about a golfer who needs more rotational velocity, I would probably start with the hip airplane. Great golfers are relatively relaxed through the downswing since muscularly generated force also adds stiffness, which slows motion. At ball contact the great ones create a pulse of muscular force throughout the linkage. This originates about the rear hip in external rotation. The "hip airplane" mimics this force.

Then I would progress to training a faster rate of relaxing the muscles to ensure the maintenance of speed in the follow through. I would avoid slow strength training for a golfer.

CW: You mentioned your work with MMA fighters. Those guys can benefit from exercises that develop rotational strength. Some of the coolest and most effective core exercises you've taught me are the ones I use with fighters.

SM: I must say I have had a lot of fun working with some of the great ones – lots of stories there. For example, one exercise I developed specifically for Georges St. Pierre was the slamball helicopter exercise. I wanted to create mammoth torsional endurance to control opponents in the clinch, but also enhance ability for explosive pulses for Muay Thai knees and those nasty inside uppercuts and body rips.

Of course, when training the isometric core endurance the challenge was to train the very brief relaxation necessary for speed to execute "dirty boxing." That's where the pulsing idea came from. As the ball passes 12 o'clock, a pulse is generated, then 6 o'clock, 3, o'clock, 9 o'clock, etc. It really challenges the neurology for speed-strength and endurance. The duty cycle is 5 minutes on, 1 minute off. Now try that for 3 or 5 rounds. It's easy on the back but brutal for the torsional musculature.

CW: Let's talk about sit-ups. Stu, there are so many guys I know that just can't get enough of them. I honestly believe that we have the Rocky movies to blame for them being so ubiquitous.
Your book Low Back Disorders was one of the first clinical-based texts that taught us sit-ups aren't very good for our discs. Your lab determined one of the primary reasons and it's due to the high compressive forces they induce, on the order of 3400N or 764 pounds. Tell us more about that.

SM: The National Institute for Occupational Safety and Health (NIOSH) sets exposure limits for substances that are known to compromise the health of the American worker. Along with obvious limits for things like poisons, radiation exposure, etc., they've found values for low back compression that lead to elevated rates of disabling back disorders.

The NIOSH have sponsored research that surveyed workers, and their data show that when lumbar loads exceed 3400N, the injury rates go up and interventions are recommended. The problem is that these are for average workers. Who's average?

Now, the sit-up recruits torso and hip muscles that impose compressive load on the spine for the average male of about 3400N. Performing sit-ups uses some training capacity – compression plus repeated bending – to achieve training of the torso and hip flexors. But remember that this combination of load and motion is a potent cause of annulus collagen delamination.

If I could give you a better tool to train the flexion muscles that preserves training capacity by sparing the most vulnerable tissues, you could then increase your tolerable training volume. This would be a great advance, of course. Consider the stir the pot exercise.

So even though sit-ups train the abdominals, psoas, and rectus femoris, the stir the pot exercise places the spine in a more resilient posture so you can really train these muscles hard.

CW: Some guys have said they listened to you and dropped doing flexion training and they became weak because of it. So they returned to doing sit-ups. What do you say?

SM: I think that they have little expertise and poor knowledge. Perhaps they're confused with the difference between flexion motion and flexion moment. In any case, flexion moment must be trained. Take the military, where speed sit-ups still form a component of the fitness test, if for no other reason than sit-ups are easy to keep score.

A good study proved that performing flexion moment challenges such as the plank actually enhanced sit-up performance in soldiers. But the problem with the military is that the soldiers train the test, and this a major reason for the number of disabled backs that are returning from tours of duty overseas. But this practice is under review, thankfully. Nonetheless, one must still train torso flexion moment but avoid the repeated movement with speed and load.

CW: I know athletes that like to perform the sit-up slowly because they really feel the burn in their abs. I have a gut feeling they think that slow movements are safer for their spine, too. However, I can't see how slow sit-ups would benefit an explosive athlete.

SM: You're right, sit-ups and slow flexion will not get you to the Olympic 100 meter final. They're not ideal for MMA fighters or NFL linebackers, either. Explosive hip flexion is required. In my lab we have a program of explosive hip flexion training with the torso locked stiff. This achieves proximal stiffness in the torso so that the full muscle force drives thigh velocity rather than the spine bending.

Furthermore, the spine must be buttressed in neutral to create the highest tolerable training capacity without the back failing with injury. Techniques to achieve this are in my book, Ultimate Back Fitness and Performance.

CW: Since sit-ups aren't ideal for sprinters, fighters, linebackers, or explosive athletes in general, what do you recommend they do?

SM: For MMA fighters, the first order of business is to create abdominal armor for their organs to survive impact. The stir the pot exercise allows brutal training without robbing training capacity from the spine. Overhead cable pulls with motion at the hips is another strength building example.

Sprints and hurdles, when combined with neural training, increase the rate of muscle activation, and most importantly, the rate of relaxation. I call this twitch training.

Of course, MMA athletes need to lift and throw and they need to strike with huge proximal stiffness and distal limb compliance, among other abilities. Technique may need to change if they have a history of spine flexion intolerance. Furthermore, they may train challenging flexion moment without actually flexing the spine. More hip mobility will help. The McGill modified curl-up with a neutral spine – perhaps supported – and barely raising the head and shoulders may be appropriate with a progression into explosive shoulder and hip flexion.

CW: Before we move on from this sit-up topic, I've got to ask you one more question. What do you think of the notion that it might be acceptable to do a thousand sit-ups or crunches every day because some guys can pull that off without any problems?

SM: First one must consider injury mechanisms from sit-ups or spinal flexion in general. Herniations and disc bulges result from repeatedly bending the spine.

For example, in a sit-up with the corresponding compressive load will eventually pump the nucleus through the annulus and bulge. If the compressive load is less, and there is no history of this process, then bending might not cause this process.

However, the argument that someone has done sit-ups their whole life and are fine so everyone should do them lacks logic and understanding – they've adapted, or they have slender spines that withstand bending, or they do not train heavy.

But here's another paradox: we all know the soft person with poor fitness who can sit with impunity and has no back pain. Yet the fit person sits at a computer and becomes pained. Bulging discs usually start with a compressive or torsional injury. Damage to the underlying trabecular bone allows the delamination process to speed up so that the flexed posture associated with sitting then causes pain.

The fit person has built up cumulative loading and bending with a few episodes of overloading the joint, while the unfit person did not. It would be very rare to find a person who can tolerate thousands of sit-ups yet has trained with substantial lifting. But those are the freaks of nature at the far end of the biological spectrum. The take home message is that if a person is lifting heavy, do not add sit-ups – choose one or the other as these two do not mix.

A final thought: If someone sits at work all day in static flexion, and then has a training session that has numerous flexion bends with moderate compressive load, sit-ups are ill advised. Did I say "no flexion?" Of course not. I said expertise is required to make the best decision to design flexion motion and flexion moment exercises.

CW: Okay, let's move on. You talk a lot about stiffening the spine during explosive actions. Can you explain what you mean?

SM: Yes, stiffening the spine will allow more explosive athleticism from the ball and socket joints of the hips and shoulders. Proximal stiffness facilitates distal explosive ability. Sprinters typically have explosive hips and sprinting is a terrific exercise, but those that succumb to a disabled back usually are not locking the pelvis and spine together when training explosive hip flexion power.

CW: You consult with enough professional athletes to make a person's head spin, especially the NFL where disc problems are rampant. What's the most common training problem you see with their training?

SM: The most common deficit of the NFL lineman I see in terms of training is their lifting form. They lose the natural lumbar curve at the bottom of the lift. Pulling from blocks helps in this regard.

Another common physical deficit is lack of lateral torso strength. This imbalance shows when the player plants a foot for a high speed cut, and the pelvis drops on the swing leg side as the spine slightly bends laterally. This is an energy leak that causes a loss in quickness and often results in instant pain. This is from an imbalance in training.

Typically these players over-emphasize the two legged lifts and pulls like squats and power cleans without considering single leg loading. In other words, the pelvis must not drop laterally with high load or high-speed single leg support. Some possible solutions are the unilateral weighted carry, sled dragging variations, one-legged hip airplanes with speed, and one-legged bounding to create a bit of a strength-speed-power continuum.

But most importantly, I must emphasize that these are just generic examples. I have to assess the player before to know what the major problem is, and the best exercise to achieve the goals while detracting as little as possible from their training capacity.

CW: Let me wrap this up by asking you what you feel are the biggest misconceptions about your training concepts? Fire away.

SM: Wow, to start I usually get quoted with a sound bite specific to a situation or athlete. Don't assume that the quote was relevant for everyone. Individuals I see come to me for a reason, and most have a back issue. Usually I have to get them back to world-class level when other approaches have failed. The approaches are special for a reason.

There also remains confusion between flexion motion and flexion moment, but this is not recognized within discussions of our work of "flexion." There are a number of laws, like Newton's laws of motion, that pertain to the back:

Keep power low.

Each person has a training capacity that when exceeded, causes injury.

Certain exercises steal training capacity and they wear out the spine before the muscles.

Certain combinations of exercises are problematic while others are synergistic.

Build proximal stiffness for distal explosive power – this means a core that is stopping motion and not creating it.

Choose exercises that spare the underlying joints when supertraining the neuromuscular elements.

Don't believe that you can train the injury mechanism.

Those are just a few.

Chad, with your work with MMA athletes, we know the number of high-level jiu-jitsu athletes who have flexion-based debilitating pain yet they need the ability to flex their spine to compete. The trick is to train around this: train flexion moment and not the movement, and save the real flexion movement for the competition. Otherwise they will never be able to compete. We have both salvaged a few careers with this approach as have a number of expert colleagues who follow these approaches.